Plotting Sound Pressure Level

Question

Articat 2018-11-26

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https://ww2.mathworks.cn/matlabcentral/answers/431919-plotting-sound-pressure-level

评论： Image Analyst 2019-1-10

help.JPG

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Hi,

So I am trying to plot the eqution:

The final solution should look like what is attached. I constructed it using a loop but I don't think I'm follwoing the right steps.. For some reason it just says R is equal to 1000 and does not give me values between 1 to 1000.

r = 45;
alpha = .005;
W = .01;
Wref = 1*10^-12;
Lw = 10*log(W/Wref)
for R = 1:1000
    Lp(R) = Lw-10*log10(2*pi*r^2)-alpha*R;
end

Thanks, anything would help.

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Articat 2018-11-26

little r is the radius of the turbine.

madhan ravi 2018-11-26

are you sure the formula is right?

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Answer 1

Image Analyst 2018-11-26

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/431919-plotting-sound-pressure-level#answer_348872

编辑：Image Analyst 2018-11-26

在 MATLAB Online 中打开

Instead of

for R = 1:1000
    Lp(R) = Lw-10*log10(2*pi*r^2)-alpha*R;
end

do it vectorized

alpha = .005;
W = .01;
Wref = 1*10^-12;
Lw = 10*log(W/Wref)
R = 1 : 1000
Lp = Lw - 10*log10(2*pi*R.^2) - alpha*R;
plot(R, Lp, 'b-', 'LineWidth', 2)
grid on;
xlabel('R', 'FontSize', 15);
ylabel('Lw', 'FontSize', 15);